Beverage whipper

ABSTRACT

A beverage whipper, including a whipper disk configured for spinning within the whipper and having a radius is disclosed. The whipper disk further includes a front surface and a plurality of forward-facing concave surfaces that divide the front surface into a plurality of front surface sections. The concave surfaces extend generally radially over more than half the radius and have a circumferential width and a depth, wherein the width is larger than the depth. The front surface sections have a total area that is at least 4-times the total area of the concave surfaces. Also, a beverage dispenser that includes the whipper for forming beverages having crema such as espresso or cappuccino.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 12/271,133 filedNov. 14, 2008, which claims the benefit of application No. 61/003,168filed Nov. 14, 2007. The entire content of each application is expresslyincorporated herein by reference thereto.

FIELD OF THE INVENTION

The present invention relates to a mixing device that provides a frothyfluid product. More particularly, the invention relates to a mixingdevice for mixing, frothing, and dispensing a beverage.

BACKGROUND OF THE INVENTION

Espresso drinks, in comparison to other coffee drinks, are noted for afine layer of bubbles (“crema”) that settles on the top of the drinkfrom fine bubbles that are interspersed within the drink during thebrewing process. Coffee consumers in many markets view a crema as a keyindicator of a good cup of espresso. Espresso and other coffee and milkdrinks are sometimes prepared by mixing a powder or fluid concentrate inwater. However, the quality perception of theses drinks is sometimes anissue if the crema does not resemble that when the espresso is preparedfrom ground coffee.

Mixing devices are known for speedier preparation of coffee, espresso,and other such beverages and other foods by mixing a powdered or liquidconcentrate food component with a liquid, such as water. These devicestypically feed the powdered or concentrate component into the water,which is often pumped tangentially into a mixing chamber to create awhirlpool to mix the powder or concentrate into the water. When theseproducts are reconstituted in a dispenser, the process does not followthe same steps as a roast and ground espresso product so a fine layercrema is not generated. Instead, a layer of undesirable large bubbles(“foam”) may be generated, the magnitude dependent on the particularrecipe of the powder or concentrate and the flow path for dispensing. Tothe consumer these bubbles could indicate that the coffee was not madecorrectly.

In known mixing devices, the mixture is then fed to a whippingmechanism, which is usually a rotating plate. The plate aerates themixture and produces a froth. The frothed mixture is usually dispensedinto a container for drinking. Such known whipping mechanisms, however,may only increase the amount of foam present in the coffee because thefroth that they produce is aimed at producing bubbles that are muchlarger than those that distinguish crema.

U.S. Pat. No. 5,927,553, for example, discloses a mixing and dispensingapparatus with a cruciform frothing blade. Other shapes of frothingblades are also known. For instance, companies such as Rhea and Zanussiuse whippers with an axially short disk with very steep sloped walls.U.S. Pat. No. 7,059,498, for example, discusses a mixing deviceincluding a conical whipping rotor that is configured to produce largebubbles within a beverage so as to form a layer of foam along the top ofthe beverage. Other whippers have disks with independent ramps extendingfrom a substantially flat plate. The known devices generally have theirgreatest efficiency for preparing a small group of products.

Therefore, there is a need for a mixing device with an improved whippingmechanism that reduces or eliminates the production of large bubbles orfoam in favor of finer bubbles.

Furthermore, crema generation is often benefited by slow flow speeds,whereas when filling a carafe with a large amount of “American style”coffee, speed is favored and crema production may not even be desirable.If dispensed into a multi-cup carafe for a server to pour from, thelarge bubbles can often prevent full filling of the carafe if they areoverflowing from the top. For this solution, a system is needed thatdoes not produce bubbles or crema and is able to rapidly fill a carafe.

SUMMARY OF THE INVENTION

An embodiment of the present invention relates to a beverage whipper.The beverage whipper includes a whipper disk having a configuration forwhipping a beverage mixture to produce a high quality crema. Theconfiguration is such that the whipper disk defines a transverse radiusand includes a front surface and a plurality of forward-facing concavesurfaces that divide the front surface into a plurality of front surfacesections. The concave surfaces extend generally radially over more thanhalf the radius and having a circumferential width and a depth. Thewidth is larger than the depth, and the front surface has an area thatis at least 4-times the area of the concave surfaces.

Preferably, the whipper disk includes a relatively sharp transitionbetween the front surface and the concave portions for promotingcavitation when the whipper is spinning. The relatively sharp transitionis preferably disposed on both circumferential sides of each of theconcave surfaces.

In a preferred embodiment, the concave surfaces are substantiallysemi-cylindrical. Further preferably, the front surface is domed in aconvex direction and can be formed having a generally ellipticalcross-section. The front surface preferably has a radially inner portionand an outer edge, the concave portion extending substantially from theinner portion to the outer edge and preferably having a width-to-depthratio of at least about 1.5 at any point along the concave surface.

Another embodiment of the present invention relates to a beveragedispenser. The beverage dispenser can also include a whipper housingdefining a cavity configured for flowing a liquid beverage mixturetherethrough, the whipper disk being rotatably disposed within thehousing cavity. A motor is operably associated with the whipper to spinthe whipper disk sufficiently fast to produce a high quality crema inthe beverage mixture. An outlet conduit is connected downstream to thehousing for dispensing the whipped beverage mixture. The dispenser alsoincludes a restrictor associated with the outlet conduit for restrictingthe flow of the whipped beverage mixture therethrough.

According to a first mode, the restrictor is preferably configured forprolonging a dwell time in which the beverage mixture is acted on by thewhipper disk. In an embodiment, a fluid-flow restrictor is disposedbetween the housing and the fluid outlet, and is configured to increasefluid back-pressure within the housing for prolonging the dwell time inwhich the beverage mixture is acted on by the whipper disk. Thepreferred restrictor is a mean to restrict the diameter of the outletconduit. In the preferred embodiment, the restrictor can be a taperedportion of the outlet conduit. Tapered portion is configured to restrictthe flow of the fluid therethrough, which can reduce the velocity of theflow of the liquid product through output conduit, which, in turn,prolongs the exposure of the fluid to the whipper disk. This can lead toincreased efficiency in the production of crema-forming bubbles. Usuallyit is preferable that the tapered portion extends over a long length ofthe outlet conduit rather than on a short length.

According to a second mode, the restrictor can be configured forbreaking up bubbles of the crema larger than a predetermined size withinthe fluid, thereby reducing the number of bubbles present within thefluid over the predetermined size. The restrictor can be in the form ofa spiral restrictor disposed within the outlet for disrupting thereducing larger bubbles in the crema. Alternatively, the restrictor candefine a plurality of holes having diameter and a length along adirection of flow that is at least as long the diameter for reducinglarger bubbles of the crema.

The beverage dispenser can be implemented according either the first orthe second above mode, yet in the preferred embodiment the beveragedispenser implements simultaneously the first and the second mode.According to this preferred mode, the beverage dispenser comprises atleast two types of restrictor: one first restrictor configured toincrease fluid back-pressure within the housing for prolonging the dwelltime in which the beverage mixture is acted on by the whipper disk and asecond restrictor configured for breaking up bubbles of the crema largerthan a predetermined size within the fluid. Said first restrictor isusually placed upstream the said second restrictor.

The beverage dispenser can also include a bypass inlet in fluidcommunication with the outlet conduit and configured for receiving afluid from a fluid source that feeds both the mixing chamber and thebypass inlet. In this embodiment, the beverage mixture is preferablyformed at a first concentration that is variable based on a volume offluid provided into the mixing chamber, and the outlet conduit isconfigured to reduce the first concentration to a lower, secondconcentration by receiving the fluid from the fluid source through thebypass inlet while the beverage mixture passes therethrough.

A further embodiment of the invention relates to a method of preparing abeverage mixture with a layer of high-quality crema. The method includesthe step of introducing a beverage mixture into a housing including awhipper disk rotatably disposed within the housing and configured forwhipping a beverage mixture to produce a high-quality crema. The methodfurther includes causing the whipper disk to spin sufficiently fast toproduce a high-quality crema in the beverage mixture, and dispensing thewhipped beverage mixture through an outlet conduit connected downstreamto the housing, the outlet conduit including a restrictor forrestricting the flow of the whipped beverage mixture through thehousing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and other advantages of the invention will becomebetter understood by reference to the following detailed description ofpreferred embodiments and the accompanying drawings wherein:

FIG. 1 is a perspective view of a whipping mechanism according to anembodiment of the present invention;

FIG. 2 is a side cross-sectional view thereof;

FIG. 3 is a top cross-sectional view thereof;

FIG. 4 is a perspective view of a whipper disk used therein;

FIG. 5 is a perspective view of a plate that can be affixed on an outputnozzle thereof; and

FIG. 6 shows an alternative embodiment of a dispensing spout configuredfor use with the whipping mechanism of FIGS. 1-5, the dispensing spoutincluding a removable sieve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-3, a preferred embodiment of the invention includesa mixing device 10 that has an input container 12. The input container12 comprises a bowl portion 14 with a tangential inlet 16 for feeding afluid under pressure. An automatically controlled valve is preferablyprovided to control the fluid flow into the input container 12. Thefluid is introduced through the tangential inlet 16 at a speed selectedto produce a swirling flow, preferably substantially a whirlpool effect.

A component to be mixed with the fluid, which may be a liquidconcentrate or a powdered food substance, is fed into an inlet 18 orinto a plurality of inlets, which are generally configured as an openingat the cover portion 20 above the bowl portion 14. Preferably, thecomponent is in the form of a liquid concentrate. The concentrate orother substance can be fed by hand or automatically by a source that isdisposed above the cover 20 of the device 10. The source preferably hasa dosing mechanism, such as a dosing screw, to automatically dose apredetermined amount of the food substance into the input container 12.A cover 20 extends around the inlet 18 or inlets and includes a lip 19,protruding into the bowl portion 14 to prevent the swirling fluid fromexiting the input container 12 by the upper side thereof. A suction isapplied to orifice 21, adjacent the underside of the lip 19 forextracting any splashed fluid material. The inlet 18 is sufficientlylarge to receive the substance poured therein and also to receive asufficient amount of air for mixing with the fluid and component.

In the embodiment shown, a throat portion 22 of the input container 12is disposed below the bowl portion 14. The throat portion 22 preferablyhas a narrower diameter than the bowl portion 14 and has a throatopening 24 disposed on a lateral side, as shown in FIG. 2. The throatportion 22 is preferably generally coaxial with the bowl portion 14 andnarrows substantially evenly along the axis of the bowl portion 14. Thisimproves the fluid flow therein and reduces any trapping of powder orother food substance. Preferably, a transition between the bowl portion14 and the throat portion 22 has an inward bend 25, followed by aconically sloped portion 27, which is followed by an outward bend 29, incross-section.

Referring to FIGS. 2 and 3, a whipper assembly 26 is in fluidcommunication with the input container, preferably at the throatopening. The whipper assembly includes a whipper disk 28. A motor 30drives disk shaft 32, which drives the whipper disk 28 so that the motor30 drives the whipper at about whipper axis 34. A motor controller ispreferably provided to control the operation and speed of the motor 30.

The preferred whipper disk 28 has a convex, substantially dome-shapedwhipper surface 36. The dome-shaped surface 36 preferably facesoutwardly with respect to the whipper axis 34. The dome shape of whippersurface 36 can be configured such that whipper surface 36 is a revolvedsurface formed from a circular arc segment. In such a configuration,whipper surface 36 is in the form of a truncated sphere having atransverse radius 38 and a surface radius 48. Preferably, transverseradius is between 5 mm and 20 mm in length. In an embodiment, transverseradius is at least about 12 mm. Preferably, transverse radius 38 isbetween 10 mm and 18 mm and more preferably about 16 mm. Surface radius48 is larger than transverse radius, and is preferably between 3 timesand 5 times larger than transverse radius. In a preferred embodiment,surface radius 48 is about 4 times larger than transverse radius 38. Inan embodiment surface radius is at least about 20 mm. In one embodiment,surface radius 48 is preferably less than about 100 mm. In a preferredembodiment, surface radius 48 is between about 30 mm and 80 mm and ismore preferably about 65 mm. Alternatively, whipper surface 36 can be asurface of revolution formed by a portion of an ellipse or other ovalshape. In such an embodiment the segment of the ellipse used to form thesurface of revolution is symmetrical about the minor axis thereof. Thewhipper surface 36 preferably has a surface area of between about 150mm² and 3000 mm². In a preferred embodiment, whipper surface 36 has asurface area of between about 500 mm² and 1500 mm², and more preferablybetween about 700 mm² and 900 mm².

A central tube 42 is formed substantially near the center of whipperdisk 28 along whipper axis 34. Whipper surface 36 surrounds central tube42 and is configured to have a surface area that is between 4.5 and 5times the transverse area of central tube 42. More preferably thesurface area of whipper surface 36 is about 4.8 times the transversearea of central tube. Preferably, a line 68 passing from the edge ofwhipper disk to the intersection of whipper surface 36 and central tube42 forms an angle 69 relative to a plane defined by the edge of whipperdisk. Angle 69 can vary with the diameter and height of whipper disk,and is preferably between about 0° and about 45°. Preferably, angle 69is between 10° and 30°. More preferably angle 69 is about 15°.Preferably, whipper disk has a height 44 that is defined as the distancebetween a plane formed by the outside edge of disc back surface 49 and aplane defined by the intersection of whipper surface 36 and central tube42. Preferably, height 44 is at least about 1 mm and at most about 15mm, more preferably is at least about 2 mm and at most about 8 mm,although other heights can be used. In an embodiment, height 44 isbetween 4 mm and 8 mm, and more preferably about 5 mm.

Whipper disk 28 includes a plurality of concave portions 60 formedthereon. That separate whipper surface 36 into segments 39. Concaveportions 60 preferably extend from the center of whipper disk 28radially outward to near the edge of whipper disk 28. In the embodimentshown, concave portions 60 have a uniform shape with respect to whippersurface 36, and the depth is not uniform, decreasing in a radial,outward direction. In an alternative embodiment, the shape and depth canbe varied or uniform. In a preferred embodiment, the width 66 and depth67 are measured at the innermost portion thereof, as shown in FIG. 4. Inan embodiment, width 66 is between about 1 and 2 times larger than thedepth 67. More preferably the width 66 is about 1.5 times larger thanthe depth 67. Preferably, each concave portion 60 extends along at least50% of the radius of whipper disk 28. In the embodiment shown in FIG. 4,the innermost end of concave portion 60 is spaced apart from whipperaxis 34 in a radial direction. Additionally, concave portion 60terminates radially inward of the outside edge of whipper disk 28. Insuch an embodiment concave portion 60 can extend along at least about75% of transverse radius 38. In other embodiments concave portion 60 canextend along at least 80% of transverse radius 38 and more preferably atleast 90%. In an embodiment, concave portions 60 may be formed so as toextend substantially all the way to the outside edge of whipper disk 28.

Whipper disk 28 can include a number of concave portions 60, andpreferably includes between 1 and 10 concave portions 60. In a preferredembodiment, whipper disk 28 includes between 2 and 6 concave portions,and more preferably includes 4 concave portions. The size, andparticularly the width 66 of concave portions 60 varies with the numberof concave portions 60 present in whipper disk 28 such that theaggregate surface area of whipper surface segments 39 is aboutthree-times the aggregate surface are of the area occupied by concaveportions 60, and more particularly about four times the aggregatesurface area. Also, the preferred concave portions 60 are substantiallyequally spaced about the whipper surface 36.

In a preferred embodiment, concave portions 60 are semicylindrical inshape. In such an embodiment, concave portions 60 extend along an axis62 and have a radius 63 such that the concave portion is defined by theintersection of the cylinder defined thereby and whipper disk 28.Accordingly, the size and shape of concave portion 60 will vary with theradius thereof, as well as the position and orientation of axis relativeto whipper disk 28. In a preferred embodiment, axis 62 is normal towhipper axis 34. In such an embodiment, as with other possibleembodiments, concave portions 60 will have a shape that tapers in theoutward direction of radius 63. As shown in FIG. 4, the width at the topof concave portions 60 decreases with the distance from whipper axis 34.Alternatively, axis 62 can be downwardly declined relative to whipperaxis 34. Preferably whipper disk 28 is spaced apart from back wall 58 ofthe whipper housing at a distance substantially equal to the height 44of whipper disk 28, although it can be slightly less by about 5 to 15%in order to give the desired size properties for concave portion.Preferably, radius 63 is between about 1 mm and 10 mm. More preferably,radius 63 is between about 3 mm and 8 mm. In a preferred embodimentradius 63 is about 4 mm. In an embodiment, radius 63 is at least about 1mm less than the height of whipper disk 28 at the apex of whippersurface 36. In an embodiment where concave portions 60 taper, thepercentage of the overall circumference of whipper surface 36 that isoccupied by the concave portions 60 in aggregate can vary with theradial distance from the whipper axis 34 at which the circumference ismeasured. In an embodiment, at the innermost end of concave portions 60,concave portions 60 can occupy at least about 50% of the totalcircumference, and more preferably about 75%. Further, at the outsideedge of whipper disk 28, concave portions 60 can occupy between about 0%and 10% of the total circumference. In one embodiment, concave portions60 can occupy 0% of the total circumference at a distance of up to 5 mmfrom the outside edge of whipper disk 26. In an embodiment, concaveportions 60 occupy about 50% of the total circumference at a radialdistance that is between about 25% and 50% of the transverse radius 38.Further, concave portions can occupy less than 25% of the totalcircumference beginning at a radial distance that is at least about 50%of the transverse radius 38, and less than about 10% of the totalcircumference at a distance that is at least about 75% of the transverseradius 38.

The edge 64 formed between whipper surface 38 and concave portion 60 ispreferably substantially sharp so as to create cavitations in the fluidexposed thereto. Preferably, an angle 65 is formed along edge 64 thatmay vary with the distance from whipper axis 34. Preferably, angle 65,when measured near the innermost portion of concave portion 60, isbetween about 30° and 90° and is more preferably about 90°. In apreferred embodiment, angle 65 preferably decreases as it extends towardthe outer edge of whipper disk 26. Whipper discs with the desirableaspects create small bubbles using a localized vacuum effect as concavecross section of the disc passes through the mixture.

The preferred whipper disk 28 is optimized to efficiently produce aquantity of bubbles within fluid based on the flow of fluidsubstantially near whipper disk 28 at a sufficient flow rate. Theformation of bubbles within the fluid is improved by the controlledcavitation within the fluid caused by movement of whipper disk 28 in avolume of fluid surrounding whipper disk 28. The structure of thepreferred whipper disk 28 is configured, according to the embodimentsdisclosed herein, to produce not only a desired quantity of bubbleswithin the fluid, but also bubbles that are generally of a smaller sizethan other known whipping devices. Specifically, when whipper disk 28 isused with a coffee product, and in particular an espresso product formedwithin mixing chamber 12 as discussed above, the bubbles formed are of asmall size sufficient to form a layer of crema when the bubbles settlealong the top of the dispensed fluid. Although bubbles within crema andwithin foam may include some bubbles of a similar size, the bubbles aregenerally much smaller within crema than within foam. In general, thepreferred whipper disk 28 is configured to increase the proportion ofsmall bubbles to large bubbles within the dispensed fluid.

Whipper disk 28 preferably includes an attachment portion near whipperaxis 34. Attachment portion is preferably in the form of a central tube42 that is configured to engage the output shaft of motor 30. Theengagement between tube 42 and the output shaft can be facilitated by aconfiguration that results in a press-fit therebetween. Preferably theparts are configured to maintain a friction fit therebetween such thatwhipper disk 28 rotates with the rotation of the motor output shaft 32.Alternatively, the tube 42 and the output shaft 32 can have matingprofiles to facilitate the mutual rotation thereof. Whipper disk 28 isdisposed within a whipper housing 52, which in the embodiment shown isintegral part of unitary construction with the input container 12.

The preferred whipper housing 52 has an inner housing surface 54 with ashape that at least partially overlies whipper disk 28. A shear gap 56is defined between the inner housing surface 54 and the circumferentialportion of the whipper surface 36 that can vary as whipper housing 52extends over whipper disk 28. Measured at the most narrow point betweenwhipper disk 28 and whipper housing 52, the shear gap 56 can be at leastabout 0.5 mm, more preferably at least about 0.8 mm, and most preferablyat least 1 mm. Measured at this location, shear gap 56 is preferably atmost about 2.5 mm and more preferably at most about 1.5 mm. In thepreferred embodiment, however, the size and configuration of the sheargap is not required in the formation of sufficiently small bubbleswithin the fluid. Rather, the configuration of whipper disk 28, itself,influences bubble formation, the whipper housing 52 being shaped toprovide both for flow of the fluid into contact with whipper disk 28 andretention of the fluid in contact with whipper disk 28. Preferably,housing 52 is structured such that as much of the fluid as possible isbrought into contact with whipper disk 28. Similarly, whipper housing 52is further structured such that the fluid remains in substantial contactwith the whipper disk 28 long enough to form an acceptable number ofbubbles therein. It is understood that when referring to the fluidcoming into contact with whipper disk 28, that direct contact is notrequired, it is simply enough that the fluid be influenced by the shapeand movement of whipper disk 28 to form the desired cavitations therein,resulting in bubbles.

Whipper disk 28 can be spaced from back wall 58. In the preferredembodiment, rear surface 49 of whipper disk 28 is spaced from back wall58 at a distance that is minimized to prevent too large a quantity offluid from passing into the space between whipper disk 28 and back wall58, but is sufficient to prevent interference by, for example, frictionbetween whipper disk 28 and back wall 58 during operation of whipperdisk 28. Accordingly, the rear surface 49 of whipper disk 28 is spacedapart from back wall 58 by at least about 0.25 mm and at most 2 mm. Morepreferably the spacing is at least about 0.5 mm, and most preferably atleast about 1 mm.

The back wall 58 preferably has a larger diameter than that of thewhipper disk 28, preferably at least about 10% to 20% larger. The outerdiameter of the back wall 58 of the preferred embodiment is at leastabout 30 mm and at most about 60 mm, while the diameter of the whipper28 is typically 20 mm to 36 mm and more preferably about 32 mm.

A product exit tube 72 is disposed downstream of the whipper disk 28 andback wall 58 and is disposed to dispense the prepared fluid mixture. Theproduct exit tube 72 is shown as an integral part of unitaryconstruction with the input container 12. The product exit tube 72preferably comprises a conduit with a diameter selected according to thefinal product that is to be dispensed. The preferred product exit tube72 has an internal diameter of about between 2 mm and 5 mm forembodiments intended to prepare several different milk and coffeebeverages. Embodiments intended primarily for coffee preferably have aproduct exit tube 72 with an internal diameter of about between 1 mm and3 mm, and in embodiments intended primarily for milk, the internaldiameter is preferably from about 4 mm to 8 mm. The diameter of theproduct exit tube 72 is selected to obtain the desired pumpingperformance from the whipper disk 28. Increasing the diameter of theconduit allows a faster flow, while decreasing the diameter providesmore back-pressure to retain the fluid mixture in the whipper assemblyand input chamber 12 for a longer time. A dispensing spout 75 ispreferably attached at the end of the product exit tube 72 for easierdispensing into a cup.

As shown in FIG. 2, dispensing spout 75 can be configured with a taperedportion 77 therein, which acts as a restrictor. Tapered portion 77 isconfigured to restrict the flow of the fluid therethrough, which canreduce the velocity of the flow of the liquid product through outputspout 72, which, in turn, prolongs the exposure of the fluid to thewhipper disk 28. This can lead to increased efficiency in the productionof crema-forming bubbles. Preferably, the smallest diameter of taperedportion 77 is at most about 95% of the size of the diameter of exit tube72 and is more preferably between 80% and 90% of the size, and is mostpreferably about 88%. Furthermore, the effectiveness of tapered portion77 can be increased by extending tapered portion 77 over a length of atleast 2 cm, and more preferably at least about 5 cm. In a preferredembodiment, tapered portion has a length of between 4 cm and 8 cm, andmore preferably about 6 cm although other lengths are possible.Preferably tapered portion is configured to restrict the flow of thefluid therethrough compared to prior whipping devices. In an embodiment,tapered portion 77 can be configured to taper further over the lengththereof. For example, tapered portion 77 diameter can continuouslydecrease until near the downstream end of the dispensing spout 75reaching a most tapered diameter that is at most about 90% of thediameter of exit tube 72. In one embodiment the downstream end oftapered portion 77 has a diameter that is between about 60% and 80% ofthe diameter of exit tube 72, and more preferably between about 65% and75%. In a preferred embodiment the diameter of the downstream end oftapered portion 77 is about 68% of the diameter of exit tube 72. Anadditional or alternative restrictor can be included within dispensingspout 75, such as a disk having an aperture formed therein that has adiameter that is smaller than that of exit tube 72.

In an embodiment, dispensing spout 75 can include a secondary inlet 86for accepting a secondary fluid supply. Preferably, the secondary fluidsupply originates from a common source as the fluid that enters mixingchamber 12 through inlet 16, which preferably includes a heater to heatthe fluid, which can be water, to a preferred temperature. The presenceof inlet 86 can be useful when a large volume of a beverage,particularly coffee, is to be prepared and dispensed in a short amountof time. A preferred embodiment of device 10 can be shaped such that theprepared fluid flows too slowly through whipper housing 54 and exit tube72 to produce a large volume thereof in a short amount of time.Accordingly, the beverage can be prepared at a higher concentration thanis preferred for drinking by providing less fluid, preferably water,through inlet 16, than would normally be used. This requires a lowervolume of fluid to pass through housing 54. Fluid, preferably water, isthen provided through secondary inlet, which passes through the outletend thereof and into the container. Preferably, the fluid flow throughsecondary inlet 86 into dispensing spout 75 is at least partiallyinfluenced by gravity. Fluid flow through secondary inlet 86 can be doneconcurrently with the output of the concentrated fluid from whipperhousing 54. The amount of fluid provided through secondary inlet 86 ispreferably suitable to provide the desired consumption concentration forthe beverage. Preferably, the device is configured to allow a userthereof to select this option. Further, secondary inlet 86 can be usedto provide an unprepared fluid, such as water, from the output end ofexit tube 72. In a further preferred embodiment, the speed of whipperdisk can be reduced during such beverage preparation and can further becompletely stopped. The downstream end of dispensing spout 75 ispreferably structured such that a cup or other beverage conveyance canbe placed therebeneath to receive the prepared beverage when dispensedfrom device 10. Further preferably, the downstream end of dispensingspout 75 is wider than the tapered portion and is further preferablywider than exit tube 72.

As shown in FIGS. 5 and 6, an output plate 80 is preferably affixed onthe end of dispensing spout 75. Output plate 80 is preferably structuredto control the rate of fluid flow therethrough such that the fluidprovided through secondary inlet properly mixes with the beveragemixture that is provided by whipper outlet 72. Output plate can alsofurther reduce or eliminate the large, undesirable bubbles when a largevolume of fluid product is dispensed. The orifices 82 in output plate 80are sized to be large enough to allow small crema bubbles to passtherethrough undisturbed, but to either break up larger bubbles or toremove them from the dispensed product. The thickness 84 of output plate80 was can also contribute to velocity reduction and the reduction inpresence of large bubbles. Preferably holes 82 are between about 1 and1.5 mm in diameter and are more preferably about 1.25 mm. The thickness84 of plate 80 is preferably between about 1 and 1.5 mm and is morepreferably about 1.25 mm. In a preferred embodiment the diameter ofopenings 82 is preferably about equal to the thickness 84 of plate.

A coil spring 88 can be fitted within dispensing spout 75. Coil spring88 is configured to disrupt the flow of fluid through exit tube 72 suchthat large bubbles are trapped therein and separated from the fluid orare, alternatively, broken up into smaller bubbles. In an embodiment,coil spring 88 can extend past the intersection of secondary inlet 86and tapered portion 77. Coil spring is preferably formed from stainlesssteel wire, although other suitable materials can be used. The overalldiameter of coil spring 88 can be structured so that coil spring 88 fitswithin exit tube 72 snugly but without causing compression thereof.Alternatively, coil spring 88 can fit loosely within exit tube 72.Alternative filter structures can be used in place of coil spring 88.

As shown in FIG. 2, a seal, such as O-ring 90, seals the space betweenthe input container 12 and the back wall member 58 and product exit tube72 area.

In use, the fluid is tangentially introduced into the input container 12through tangential inlet 16. In the preferred embodiment, the fluidcomprises water, and the flow rate is about between 3 mL/sec and 30mL/sec, more preferably about between 5 mL/sec and 15 mL/sec, and mostpreferably about between 9 mL/sec and 12 mL/sec. At the time orpreferably after the water flow into the input container 12 iscommenced, a powdered food component, such as a powdered coffee productand/or powdered milk, is dosed into the water through powder inlet 18.Alternatively, a fluid concentrate can be used in addition to or insteadof a powder. Preferably the powder dosing begins at least about 0.1 secafter the water dosing begins and more preferably at least about 0.3sec. later, and preferably at most about 3 sec later, and morepreferably at most about 1 sec later. Preferably the water is continuedto be fed into the input container 12 until the powder dosing isstopped, and preferably at most about 8 sec after the powder dosingends, and more preferably at most about 3 sec later, and preferably atleast about 1 sec later. When a liquid concentrate is used in place ofthe powder, the same process steps are implemented.

The water and powder start getting mixed in the swirling flow within theinput container 12, including the throat portion 22. The whipper disk 28is rotated by the motor 30 at a speed sufficient for pumping the mixturetowards the product exit tube 72 and for producing the desired foamingand aeration effect. The whipper disk 28 sucks in air for incorporationinto the mixture. The speed of the whipper disk 28 is preferablyvariable to enable a speed selection to deliver the desired amount ofenergy to the mixture to produce the desired frothing. For obtainingproducts of certain qualities, the rotation speed of the whipper disk 28can be varied between two or more speeds during the preparation of asingle product. Device 10 is preferably structured to provide a layer offroth, that is similar in thickness and bubble size to that of crema,especially on beverages like coffee or espresso. Device 10, for example,can provide a high specific energy dissipation to generate a milk frothand a moderately low specific energy dissipation to obtain ahigh-quality coffee crema in the same unit. The frothed product is thendispensed through the product exit tube 72.

The energy dissipation of the device can be controlled by adjusting thedisk speed, and product flow rate, although these quantities areinterdependent. An increase in disk speed and a decrease in flow ratewill provide a higher energy dissipation. The preferred flow rate isbetween at least about 5 g/sec and up to about 30 g/sec, and morepreferably at least about 8 g/sec and up to about 15 g/sec. Theflow-rate of the system can be controlled using one or more of thepreviously-discussed restrictor devices. In a preferred embodiment, theflow rate is optimized for the desired high quality crema formation andis at most about 10 g/sec, and is preferably less than about 8 g/s.Also, if rpm is increased, noise and cost of the machine will increaseas well.

The preferred embodiments described above allow a device of compactsize, and with a desirable flow rate for preparing individual drinks tobe provided without requiring extremely high disk speeds, such as ofabove about 30,000 rpm. Preferably, the disk speed is at least about5,000 rpm and at most about 25,000 rpm, more preferably is at leastabout 10,000 rpm and at most about 15,000 rpm, although other speeds canbe used. At these rotation speeds, whipper disk can have a transversediameter 38 of about 18 mm or greater. Raising and lowering the diskspeed can produce different characteristics for the beverage. Furtherthe combination of a frothed beverage produced using the whipperaccording to different speeds and the addition or not of a non-frothedliquid from bypass inlet 86 can further vary the beveragecharacteristics.

While illustrative embodiments of the invention are disclosed herein, itwill be appreciated that numerous modifications and other embodimentsmay be devised by those skilled in the art. For example, the whipperdisk may have an inward facing whipper surface and rotate with respectto a portion of the whipper housing that extends inside the whipper.Therefore, it will be understood that the appended claims are intendedto cover all such modifications and embodiments that come within thespirit and scope of the present invention.

1. A beverage whipper, comprising a whipper disk having a configurationfor whipping a beverage mixture to produce a crema, the configurationbeing such that the whipper disk defines a transverse radius andincludes a front surface and a plurality of forward-facing concavesurfaces that divide the front surface into a plurality of front surfacesections, the concave surfaces extending radially over more than halfthe radius and having a circumferential width and a depth, wherein thewidth is larger than the depth, and wherein the front surface has anarea that is at least 4 times the area of the concave surfaces.
 2. Thewhipper of claim 1, wherein the whipper disk comprises a relativelysharp transition between the front surface and the concave portions forpromoting cavitation when the whipper is spinning.
 3. The whipper ofclaim 2, wherein the relatively sharp transition is disposed on bothcircumferential sides of each of the concave surfaces.
 4. The whipper ofclaim 1, wherein the concave surfaces are substantiallysemi-cylindrical.
 5. The whipper of claim 1, wherein the front surfaceis domed in a convex direction.
 6. The whipper of claim 5, wherein thefront surface has a generally elliptical cross-section.
 7. The whipperof claim 1, wherein the front surface has a radially inner portion andan outer edge, the concave portion extending substantially from theinner portion to the outer edge.
 8. The whipper of claim 1, wherein theconcave surfaces have a width-to-depth ratio of at least about 1.5. 9.The whipper of claim 1, operatively associated with an outlet fordelivering a whipped beverage mixture that contains the crema, whereinthe outlet comprises a restrictor associated for restricting the flow ofthe whipped beverage mixture therethrough.
 10. The whipper of claim 9,wherein the restrictor is configured for prolonging a dwell time inwhich the beverage mixture is acted on by the whipper disk.
 11. Thewhipper of claim 9, wherein the restrictor is configured to increasefluid back pressure for prolonging a dwell time in which the beveragemixture is acted on by the whipper disk.
 12. The whipper of claim 11,wherein the restrictor includes a tapered portion for providing thefluid back pressure.
 13. The whipper of claim 1, operatively associatedwith an outlet for delivering a whipped beverage mixture that containsthe crema, wherein the outlet comprises a filter disposed therein andconfigured for breaking up bubbles of the crema larger than apredetermined size within the fluid, thereby reducing the number ofbubbles present within the fluid over the predetermined size.
 14. Thewhipper of claim 13, wherein the filter defines a plurality of holeshaving diameter and a length along a direction of flow that is at leastas long the diameter for reducing larger bubbles of the crema.
 15. Thewhipper of claim 13, wherein the filter comprises a spiral filterdisposed within the outlet for disrupting the reducing larger bubbles inthe crema.
 16. A method of preparing a beverage mixture with a layer ofhigh-quality crema, which comprises: whipping a beverage mixture withthe whipper of claim 1, wherein the whipper spins sufficiently fast toproduce a crema in the beverage mixture; and dispensing the whippedbeverage mixture through an outlet that is associated with the whipper.17. The method of claim 16, wherein the beverage mixture comprisescoffee and the whipper prepares an espresso or cappuccino.